Automatic spark-timer for internal-combustion engines.



J. J. HERZOG & W. M. MEDLOCK.

AUTOMATIC SPARK TIMER FOR INTERNAL COMBUSTION ENGINES.

APPLICATION FILED NOV. 24, 1915- 1,221,]. 76. Patented Apr. 3, 1917 3 SHEETS-SHEEI' 2.

WITNESSES: I mmvrons fg j- ATTORNEYS I. I. HERZOG & W. M. MEDLOCK. AUTOMATIC SPARK TIMER FOR INTERNAL'COMBUSTION ENGINES.

W3 mm wm M M mm H @MJM t 1 h w APPLICATION FILED NOV. 24, I915.

, WWHI I M I WH I M & wmw m I r W 1 4 ATTORNEYS UNITED sTATEs PATENT OFFICE.

JOSEPH J. HEB-20G AND WALTER M. MEDLOCK, OI MOBILE, ALABAMA, ASSIGNOBS OF ONE-THIRD '10 LUCIOUS GENEVE ADAMS, OF MOBILE, ALABAMA.

. Specification of Letters Patent.

Patented Apr. 3, 1917.

Application filed November 24, 1916. Serial No. 63,218.

device by means of which the ignition spark.

of an internal combustion engine may be so timed that no matter at what speed the engine is running the cylinders will befired at the precise moment to give a maximum efficiency.

A further object of our invention is to provide a device of the type described for use on automobiles, thereby obviating the necessity of manual manipulation of the spark lever, so that an automobile may be run at a very low speed or at a high speed or at intermediate speeds without unevenness or jerking of the car due to failure to shift the spark leverto the proper position.

A further object of our invention is to provide a device of the type described, in which the control of the time of ignition is effected by means of a centrifugal device so arranged that as the centrifugal force increases according to the well-known law (that is to say, in proportion to the square of the speed) the effective force exerted by the centrifugal device increases substantially in direct proportion to the speed or more strictly speaking, increases in exact proportion to the distance to which the spark tim ing device must be moved for the most efficient working of the engine.

A further object of our invention is to provide a device of the type described, having a novel form of centrifugal device provided with a cam portion whose cam curve is formed so that as the speed increases the leverage decreases.

My invention is illustrated in the accompa'nying drawings forming part of this application, in which similar reference characters indicate like parts in the several views, and in which- Figure 1 is a perspective view showing one embodiment of the invention,

Fig. 2 is a diagrammatic view of the circult connections showing the device applied to a low voltage generator connected with a single transformer or coil,

Flg. 3 is a perspective view showing a portion of the device,

Fig. 4 is a perspective view of a portion of the distributer,

Fig. 5 is a perspectix e view somewhat similar to Fig. 3 but with certain parts removed to show the interior construction,

Fig. 6 is a perspective view showing a portion'of the make-and-break mechanism,

Fig. 7 is a perspective view showing a portion of the centrifugal device,

Fig. 8 is a central sectional view through the device,

Fig. 9 1s a section on the line 9-9 of Fig. 8,

Fig. 10 is a diagrammatic view showing the relation of the centrifugal device with respect to the removable arm of the distributer when the speed of the engine is normal, as when the automobile or vehicle is running steadily at its normal speed, and

Figs. 11 and 12 are diagrammatic views similar to Fig. 10, but showing the parts in shifted position, due to the changed speed of the engine.

In carrying out our invention we provide a housing which consists preferably of a casting of aluminum or other suitable metal having at its lower end a cap 1 which is provided with laterally extending arms 2 provided with bolt holes by means of which the device may be secured to the engine frame 3, as shown in Fig. 1. In this figure the device is shown as applied to a low priced car of a popular make, but it Will be understood that it may be used on the engines of other cars, Without departing from the spirit of the invention.

The cap 1 is designed to fit into the shell 4 of the ordinary commutator and to take the place of'the cap now in ordinary use. The cap 1 is connected to an integral casing 5 by means of a post 6 which is provided with a bore 7 arranged to receive a shaft 8. The latter extends into the cap 1 and is provided with a bevel gear 9 arranged to engas gage a similar bevel gear 10 on the cam shaft 11.

The casing 5, as will be seen from the drawings, is cylindrical in form. The shaft 8 extends into the casing and secured to the shaft is a plate 12, having an integral collar secured to the shaft by means of a set screw 13, or in any other suitable manner. T'hlS plate forms a sup-port for the centrifugal device as will be hereinafter explained.

Consider now Figs. 1 and 6. In Fig. 6 we have shown certain parts which are formed integrally. These parts consist of a sleeve 14, a bar 15, connecting parts 16 and 17, whose peculiar shapes have no significance, these shapes being merely for ease in machining, a make-and-break wheel 18, this make-and-break wheel being made by inserting at equi-distant points insulating material 19, and a stub shaft 20. These integral parts are rotatable with respect to the shaft 8.

Carried by the plate 12 are pivot pins 21 and 22. Upon the former is pivotally mounted a centrifugal member 23, While a similar centrifugal member 24 is mounted on the pin 22, see Figs. 9, 10 and 11. Each of these centrifugal members 23 and 24 is provided with a cam surface arranged to engage the bar or lever 15. The contours of these cam surfaces are precisel the same and a description of one wil suffice for both. In Figs. 9, 10 and 11, it will be observed that the cam surface of the centrifugal member 23 is curved at the ends, as shown at 23 and 23 and is substantially flat at the intermediate portion as shown at 23. The reason for forming the contour of the cam sur face in this manner will be explained later. Each of the centrifugal members 23 and 24 is held in close engagement with the lever 15 by means of springs such as those shown at 25, one end being attached to the centrifugal member and the other to the lever.

Secured to the inner side of the casing 5 is an arm 26 which bears a contact roller 27 This arm 26 is insulated from the easing 5 and is connected to a binding post 28 on the outside of the casing. The roller 27 is designed to engage the make-and-break wheel which is formed by the conducting portions 18 and the insulating portions 19.

Disposed within the casing 5 is a partition 29 having a central opening arranged to fit over the stub shaft 20. This partition forms a bearing for the stub shaft 20. A cap 30 is arranged to cover the open end of the casing 5. This cap has a pin 31 arranged to enter an opening 32 in the casing 5, the opposite side of the casing being provided with a spring clasp 33 for holding the cap in position. The cap 30 bears a housing 34 for a rotatable arm 35. The latter is carried by an integral plate 36 which has a hub 37 provided with a metal lining sleeve 37 that is keyed or otherwise secured to the end of the stub shaft 20, so that the plate 36 and the arm 35 revolve with the stub shaft.

Secured to the arm 35 is a conducting bar 38 having an opening arranged to register with a similar opening in the arm A conducting wiper or brush 39 which is preferably made of carbon is provided with a spring 40 which normally tends to force the brush or wiper outwardly so as to engage the fixed contacts 41, 41 341, and 41 as-the arm is rotated, these fixed contacts being carried by the end 42 of the housing 34. Binding posts 43, 43", 43 and 43 connect with their respective fixed contacts.- A central binding post 44 is electrically connected with a spring pressed contact pin 45 whose end is arranged to enter a recess 46 on the top of the conducting portion 38 for the purpose of affording electrical contact between the binding post 44 and the conducting member 38.

From the foregoing description of the various parts of the device the operation thereof may be readily understood.

As stated heretofore the device is secured in a position shown in Fig. 1. In this position it will be observed that the axial line of the post 6 and of the casing 5 is inclined. This is for the reason that for the particular engine which we have in mind the inclination of the device brings it into a position in which it does not interfere with the fan belt 45, see Fig. 1. The device is connected up, as shown in Fig. 2, in which figure the generator G is connected with a switch Sw which in turn is connected with a primarv P of the transformer or coil. One terminal of the latter is connected with the roller 27 which rests on the make-and-break Wheel formed by the conducting portions 18 and insulating portions 19. The conducting portions 18 of the make-and-break wheel are grounded as is also one side of the generator G, thus making a complete primary circuit, when the roller 27 engages one of the conducting portions 18.

The secondary S of the transformer has one terminal grounded, the other terminal being connected with the binding post 44 and in turn with the conducting arm 38. The binding posts 43, 43 43 and 43 which are connected to the stationary contacts 41, 41", 41 and 41 respectively, are also connected with the spark plugs of the cylinders No. 1, No. 2, No. 4 and No. 3 respectively.

It will be obvious that as the cam shaft 11 is turned it will cause the rotation of the shaft 8 and that the faster the engine runs the faster the shaft 8 will rotate. The centrifugal members 23' and 24 will tend to swing outwardly and this will tend to shift the lever 15 with respect to the plate 12 to which the centrifugal members are pivoted.

make-and-break wheel and also with the conducting portion 38 of the rotatable arm of the distributer and therefore the time at which contacts are made by the roller 27 with the conducting portions 18 of the makeand-break device and the brush or wiper 39 with the fixed contacts 41, 41*, 41 and 41 will be either retarded or advanced.

Consider for the moment the diagram of the circuit connections as shown in Fig. 2. With the parts in the position shown in the figure current will pass from the generator G, through the switch Sw, primary P of the conducting coil, roller 27, conducting portion 18 of the make-and-break piece, and to ground. The secondary source of current S will cause a spark to pass at the terminals of the spark plug in cylinder No. 1, the current passing from the secondary coil, through 44, arm 38, 43*, through the spark plug, through ground and to the coil S.

It will be noted that the conducting portions 18 of the make and break wheel are disposed in definite and fixed relation to the fixed contacts of the distributer and the rotating arm of the latter. If now the makeand-break Wheel and the rotatable arm of the distributer be shifted simultaneously either in one direction or the other, the ignition will be correspondingly advanced or retarded. This is what occurs when the centrifugal members 23 and 24 are moved outwardly by increased speed or are drawn inwardly by the springs 25 when the speed decreases.

A feature to which we desire to call particular attention is the fact that the leverage which is exerted by the cam portion of the centrifugal devices 23 and 24: does not increase with the centrifugal force which, as stated before, varies as the square of the speed, but increases only in such ratio as to shift the make-and-break wheel and the conducting arm of the distributer, so as to secure the best results. In order to do this it is necessary that the leverage exerted by the centrifugal members 23 and 2% be decreased as the centrifugal force increases. Furthermore, it is necessary to cut the cam members on a special cam curve or contour.

Referring now to Fig. 9 it will be seen that the springs 25 hold the centrifugal members 23 and 2% in contact with the lever. The contacting point is at a maximum dis tance from the center of the lever. As the machine speeds up and the centrifugal 11l8111 bers 23 and 24: move outwardly this contacting point shifts toward the center of the lever, thereby decreasing the leverage.

In the ordinary operation of an automobile, the automobile is started and is speeded up to the ordinary running speed, say from fourteen to seventeen miles an hour, and between these points the spark lever should be only slightly advanced.

It will be noted that we have provided a flat portion such as that shown at 2. by means of which the centrifugal members may have a slight outward movement due to the increased speed over, say fourteen miles an hour, without advancing the time of sparking proportionately. This condition is shown in Fig. 10.

When now the speed is increased as shown m Fig. 11, the outward movement of the centrifugal members 23 and 24 will cause a further shifting of the lever 15, but as will be plainly seen from Fig. 11 the leverage is greatly decreased. The cam curve or contour must accord to given conditions, that is to say, with an engine having parts of given size the cam curve is found by experiment so that the curve which is finally decided on is the one which will best control the time of ignition. It is obvious that under other conditions the form of curve might be varied without departing from the spirit of the invention. It is, however, essential to our invention that the leverage be decreased as the centrifugal force increases. In Fig. 10 it will be observed that the roller 27 is just about to engage a conducting segment 18 of the make-and-break wheel, the vehicle being at normal speed. When now the speed increases, say to twenty-two miles an hour, the centrifugal. members 23 and 24 will fiy outwardly, thereby moving the lever 15 from the position shown in Fig. 10 to that shown in Fig. 11. This will cause the advance of the make-and-break wheel and also of the distributing arm 38, so that the roller 27 is now engaging a conducting portion 18 while the wiper 39 is engaging the fixed contact 41. It will be understood that in Figs. 10 and 11 the plate 12 is shown in the same relative position and that the shifting of the make-and-break wheel and the distributing arm is accomplished by the increased speed in the manner described.

The device has been tried out in prac tice and a car has been run under adverse conditions through sand and over rough roads and up steep hills. and in each instance the automatic spark timing device has shift ed the make-and-breakwheel and the arm of the distributer so as to time the ignition to secure the best results.

We claim 1. An automatic spark timing device for internal combustion engines, comprising a rotatable contact wheel, and means for advancing or retarding the contact wheel. said means including a lever secured to said contact wheel, a pair of centrifugal devices on opposite sides of said lever and arranged to engage the lever, the leverage exerted by said centrifugal devices decreasing as the centrifugal force increases.

2. An automatic spark timing device for internal combustion engines. comprising a contact wheel, a distributing arm, a lever for shifting said contact wheel and said distributing arm, centrifugal devices actuated by the engine shaft for moving the lever so as to shift the contact wheel and the distributing arm, the leverage exerted by said centrifugal devices increasing as the centrifugal force increases, and a series of stationary contacts arranged to be engaged by the distributing arm.

3. In an automatic spark timing device for internal combustion engines, a shaft, a pivoted centrifugal member secured to said shaft, a lever pivotally mounted on said shaft, a make and break wheel and a movable contact member connected with said lever and movable therewith, said centrifugal member having a cam surface arranged to engage said lever for shifting the latter relatively to the shaft upon which it is pivoted.

4. In an automatic spark timing device for internal combustion engines, a shaft, a pivoted centrifugal member secured to said shaft, a lever pivotally mounted on said shaft, a make and breakwheel and a movable distributing arm connected with said lever and movable therewith, said centrifugal member having a cam surface arranged to engage said lever for shifting the latter relatively to the shaft upon which it is pivoted, the contour of the cam surface being such that as the centrifugal force increases the leverage exerted by the cam on the lever is decreased.

'5. In an automatic spark timing device for internal combustion engines, a make and break wheel, a rotatable distributing arm, connections between said wheel and said arm for causing the two to move together, a retatable shaft, a centrifugal device operated by said shaft, and means actuated by said centrifugal device for causing a relative movement between said make and break wheel and the said rotatable shaft.

6. In an automatic spark timing device for internal combustion engines, a rotatable shaft, a lever pivotally mounted on said shaft, a make and break wheel, and a movable distributing arm rigidly connected with said lever, and a centrifugal device operated by the rotation of said shaft for moving the lever relatively to the shaft.

7. In an automatic spark timing device for internal combustion engines, a rotatable shaft, a lever pivotally mounted on said shaft, a make and break wheel, and a movable distributing arm rigidly connected with said lever, and a centrifugal device operated by the rotation of said shaft for moving the lever relatively to the shaft, said centrifugal device being pivotally mounted and hav ing one end arranged to engage the lever, the leverage exerted by said centrifugal device decreasing as the centrifugal force increases.

8. In an automatic spark timing device for internal combustion engines, a rotatable shaft, electrical sparking contacts rotatable through the medium of said shaft, and adapted to move relatively to said shaft, a spring for normally retaining the contacts in fixed relation to the shaft, a centrifugal device operated by the rotation of the shaft for moving the contacts relatively to the shaft, the leverage exerted by the centrifugal device being substantially constant irrespective of the centrifugal force developed through the rotation of the shaft.

9. In an automatic spark timing device for internal combustion engines, a rotatable shaft, a lever pivotally mounted on said shaft, a series of sparking contacts connected with said lever, a centrifugal device actuated through the rotation of the shaft, one end of said centrifugal device being in engagement with said lever for moving the latter, a spring for normally keepin said lever in fixed relation with said sha t, the leverage exerted by said centrifugal device decreasing as the centrifugal force increases.

10. In an automatic spark timing device for internal combustion engines, a rotatable shaft, a plate secured on said shaft, 2. centrifugal device pivotally mounted on said plate, a lever pivotally mounted on said shaft, and springs connecting said lever with said centrifugal device, one end of said centrifugal device bearing on the lever, movable contacts secured to said lever, and rotatable therewith, the centrifugal force developed by the rotating shaft serving to move the centrifugal device so as to shift the lever with respect to the plate, the leverage exerted by said centrifugal device decreasing as the centrifugal force increases.

11. In an automatic spark timing device for internal combustion engines, a shaft, a plate secured to said shaft and revoluble therewith, a pair of pivoted centrifugal members carried by said plate, a lever pivotally mounted on said shaft and being arranged to be engaged by the centrifugal devices, a contact wheel secured to said lever and movable therewith, springs connecting said lever with the engaging ends of the centrifugal devices, said engaging ends being provided with cam curves soarranged that the leverage exerted by the centrifugal devices is decreased as the centrifugal force is increased.

12. In an automatic spark timing device for internal combustion engines, a rotatable shaft, a plate secured to the shaft near one end thereof, a lever pivotally mounted on the end of the shaft, a contact wheel carried by the lever, a centrifugal member pivoted to the plate on each side of said lever, the inner ends of said centrifugal members being arranged to engage opposite sides of the lever and being constructed. on cam curves so arranged that the leverage is decreased as thecentrifugal devices move outwardly-under action of centrifugal force, and a spring connecting the engaging ends of the centrifugal devices With the corresponding ends of the lever for opposing the outward movement of the centrifugal devices.

13. In an automatic spark timing device for internal combustion engines, a rotatable shaft, a plate secured to the shaft near one end thereof, alever pivotally mounted on the end of the shaft, a contact wheel carried by the lever, a centrifugal member pivoted to the plate on each side of said lever, the in'ner ends ofsaid centrifugal members being arranged to engage opposite sides of the lever and being constructed on cam curves so arranged that the leverage is decreased as the centrifugal devices move outwardly under action of centrifugal force, a spring connecting the engaging ends of the centrifugal devices with vthe corresponding ends of the lever for opposing the outward movement of the centrifugal devices, a plurality of fixed contacts, and aconducting arm secured to said contact wheel and insulated therefrom, said conducting arm being rotatable with said contact Wheel and being arranged to engage said fixed contacts successively.

14. In an automatic spark timing device for internal combustion engines, a rotatable shaft, a plate secured to the shaft near one end thereof, a lever pivotally mounted on the end of the shaft, a contact wheel carried by the lever, a centrifugal member pivoted to the plate on each side of said lever, the inner ends of said centrifugalmembers being arranged to engage opposite'sides of the lever and being constructed on cam curves so arranged that the leverage is de creased as the centrifugal devices move outwardly under action of centrifugal force, a spring connecting the engaging ends of the centrifugal devices with the corresponding ends of the lever for opposing the outward movement of the centrifugal devices, a plurality of fixed contacts, a conducting arm secured to said contact wheel and insulated therefrom, said conducting arm being rotatable with said contact wheel, and a spring pressed wiper carried by said rotatable conducting arm and arranged to engage said fixed contacts.

JOSEPH J. HERZOG. WALTER M. MEDLOCK. 

